﻿using System;
using Xpedite.Config;
using Xpedite.Extensions;
using Xpedite.Resources;
using Xpedite.Resources.Builders;
using Xpedite.Resources.Compressors;
using Xpedite.Resources.Loaders;
using Xpedite.WebAbstraction;

/* Copyright (c) 2010 CBaxter
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
 * IN THE SOFTWARE. 
 */

namespace Xpedite.Handlers
{
  internal class MinificationHandler
  {
    private readonly IResourceLoaderFactory _loaderFactory;
    private readonly ICompressorFactory _compressorFactory;
    private readonly ConfigMode _mode;

    public MinificationHandler(ConfigMode mode, ICompressorFactory compressorFactory)
      : this(mode, compressorFactory, new ResourceLoaderFactory())
    { }

    internal MinificationHandler(ConfigMode mode, ICompressorFactory compressorFactory, IResourceLoaderFactory loaderFactory)
    {
      Verify.NotNull(compressorFactory, "compressorFactory");
      Verify.NotNull(loaderFactory, "loaderFactory");

      _compressorFactory = compressorFactory;
      _loaderFactory = loaderFactory;
      _mode = mode;
    }

    public void ProcessRequest(IWebContext context, ResourceType resourceType)
    {
      IResourceCache resourceCache = context.GetResourceCache();

      try
      {
        IResource resource =  _mode == ConfigMode.Off || _mode == ConfigMode.RemoteOnly && context.Request.IsLocal
                                ? GetDebugResource(context, resourceType)
                                : GetCachedResource(context, resourceType, resourceCache);

        if (ResourceNotModified(context.Request, resource))
          context.Response.NotModified();
        else
          context.Response.SendResource(resource, _compressorFactory.Create(context.Request.Headers[WebRequestHeader.AcceptEncoding] ?? String.Empty));
      }
      catch
      {
        resourceCache.Remove(new ResourceUrl(context.Request));
        throw;
      }
    }

    private IResource GetDebugResource(IWebContext context, ResourceType resourceType)
    {
      IWebRequest request = context.Request;
      IResourceUrl resourceUrl = new ResourceUrl(request, request.Url);
      ResourceData data = _loaderFactory.Create(resourceUrl).LoadData();

      return new Resource
        {
          Type = resourceType,
          Bytes = data.Bytes,
          LastModified = data.LastModified,
          Encoding = data.Encoding,
          Compressable = true
        };
    }
    
    private static IResource GetCachedResource(IWebContext context, ResourceType resourceType, IResourceCache resourceCache)
    {
      IWebRequest request = context.Request;
      IResourceUrl resourceUrl = new ResourceUrl(request, request.Url);
      IResourceBuilderFactory resourceBuilderFactory = context.GetResourceBuilderFactory();

      return resourceCache.GetOrCreateWithFileDependency(
               new ResourceUrl(request),
               () => resourceBuilderFactory.Create(resourceType, resourceUrl).Build(),
               resourceUrl.PhysicalPath
             ).Resource;
    }
    
    private static Boolean ResourceNotModified(IWebRequest request, IResource resource)
    {
      return String.Compare(request.Headers[WebRequestHeader.IfModifiedSince] ?? String.Empty, resource.LastModified.ToString(DateFormat.RFC1123), StringComparison.OrdinalIgnoreCase) == 0;
    }
  }
}
